Do a little bit of documentation and optimization for some of the current save-related routines.

Some of the logic wasn't very clear from just looking at the code and some of it also wasn't very optimal.
So I added some comments and optimized some stuff to make it better.

include/flash_mem.h

@@ -15,10 +15,25 @@ extern char mem_name;
 extern u8 global_memory_buffer[0x1000];
 extern rom_data curr_GBA_rom;
 
-void initalize_memory_locations();
+/**
+ * @brief Given that the save sections within a save slot are not saved in a fixed order,
+ * This function will walk through the save slot to fill the memory_section_array map.
+ * 
+ * After calling this, memory_section_array will point to the save offset by each section ID. 
+ * So memory_section_array[0] will point to the save offset of section 0, etc.
+ */
+void initialize_memory_locations();
+
 void print_mem_section();
 //bool insert_pokemon(Pokemon party_array[], int num);
 void reverse_endian(u8 *data, size_t size);
+
+/**
+ * @brief This function will update the checksum in global_memory_buffer.
+ * It assumes that global_memory_buffer contains one of the save data sections.
+ * 
+ * @param hall_of_fame This is needed to indicate if you're trying to save the hall of fame section. The checksum offset is slightly different there.
+ */
 void update_memory_buffer_checksum(bool hall_of_fame);
 bool read_flag(u16 flag_id);
 bool compare_map_and_npc_data(int map_bank, int map_id, int npc_id);

include/mystery_gift_builder.h

@@ -4,7 +4,7 @@
 #include <tonc.h>
 #include "pokemon_party.h"
 #include "debug_mode.h"
-#include "save_data_manager.h"
+#include "ptgb_save_data_manager.h"
 #include "script_var.h"
 #include "pokemon_data.h"
 

include/ptgb_save_data_manager.h

@@ -1,12 +1,14 @@
-#ifndef SAVE_DATA_MANAGER_H
+#ifndef PTGB_SAVE_DATA_MANAGER_H
-#define SAVE_DATA_MANAGER_H
+#define PTGB_SAVE_DATA_MANAGER_H
 
-#include <tonc.h>
 #include "rom_data.h"
 
 #define HALL_OF_FAME 0x01C000
 #define HOF_SECTION 2032
 
+// NOTE: This module doesn't manage the _game_ save. It manages Poke_Transporter's specific save data.
+// This save data is stored at an unused section (HOF_SECTION) of the HALL OF FAME save section.
+
 // Data map:
 // There are 1936 (0x790) unused bytes starting at 0x1D7F0
 
@@ -27,7 +29,7 @@ void set_def_lang(int nLang);
 int get_def_lang_num();
 bool get_tutorial_flag();
 void set_tutorial_flag(bool value);
-void initalize_save_data();
+void initialize_save_data();
 int get_dex_completion(int gen, bool include_mythicals);
 bool check_can_save();
 #endif

source/box_menu.cpp

@@ -2,7 +2,7 @@
 #include "typeDefs.h"
 #include "button_menu.h"
 #include "button_handler.h"
-#include "save_data_manager.h"
+#include "ptgb_save_data_manager.h"
 #include "global_frame_controller.h"
 #include "string"
 #include "sprite_data.h"

source/button_menu.cpp

@@ -1,7 +1,7 @@
 #include <tonc.h>
 #include "button_menu.h"
 #include "button_handler.h"
-#include "save_data_manager.h"
+#include "ptgb_save_data_manager.h"
 #include "global_frame_controller.h"
 #include "string"
 

source/flash_mem.cpp

@@ -6,19 +6,17 @@
 #include "libraries/Pokemon-Gen3-to-Gen-X/include/save.h"
 #include "text_engine.h"
 
-#define pkmn_length 80
+#define READ_SAVE_SECTIONS 14
-#define READ_SAVE_SECTIONS 5
 #define TOTAL_SAVE_SECTIONS 14
 
 vu32 newest_save_offset = SAVE_A_OFFSET;
 
-vu32 memory_section_array[READ_SAVE_SECTIONS] = {};
+vu32 memory_section_array[READ_SAVE_SECTIONS];
 u8 global_memory_buffer[0x1000];
-char mem_name = 'A';
 u8 mem_id;
 
 // Fills the variables with the current offset information
-void initalize_memory_locations()
+void initialize_memory_locations()
 {
     u8 save_A_index[4];
     u8 save_B_index[4];
@@ -31,10 +29,12 @@ void initalize_memory_locations()
     if (*(vu32 *)save_B_index > *(vu32 *)save_A_index)
     {
         newest_save_offset = SAVE_B_OFFSET;
-        mem_name = 'B';
     }
 
     // Populates the memory_section_array with the correct pointer locations
+    // The sections within the save slot are rotated on every save. So it doesn't 
+    // start at the first section. However, the next sections follow sequentially.
+    // https://bulbapedia.bulbagarden.net/wiki/Save_data_structure_(Generation_III)#Section_ID
     copy_save_to_ram(newest_save_offset + SECTION_ID_OFFSET, &mem_id, 1);
     for (int i = 0; i < TOTAL_SAVE_SECTIONS; i++)
     {
@@ -99,6 +99,7 @@ void print_mem_section()
     /*
     uint16_t charset[256];
     byte out[4] = {0, 0, 0, 0xFF};
+    const char mem_name = (newest_save_offset == SAVE_A_OFFSET) ? 'A' : 'B';
 
     load_localized_charset(charset, 3, ENGLISH);
 
@@ -124,33 +125,28 @@ void reverse_endian(u8 *data, size_t size)
 
 void update_memory_buffer_checksum(bool hall_of_fame)
 {
-    vu32 checksum = 0x00;
+    u32 checksum = 0x00;
 
-    vu32 num_of_bytes = 3968;
+    // Section 13 is the last PC buffer (I) and that one only has 2000 bytes of data.
-    if (global_memory_buffer[0x0FF4] == 13)
+    // source: https://bulbapedia.bulbagarden.net/wiki/Save_data_structure_(Generation_III)#Section_ID
+    const u32 num_of_bytes = (global_memory_buffer[SECTION_ID_OFFSET] != 13) ? 3968 : 2000;
+
+    // the cpu is little endian and the data is read as little endian too.
+    // therefore, we can do a straightforward sum of the data as u32's.
+    const u32 *cur = (const u32 *)global_memory_buffer;
+    const u32 * const end = (const u32 *)(global_memory_buffer + num_of_bytes);
+    while (cur < end)
     {
-        num_of_bytes = 2000;
+        checksum += *cur;
+        ++cur;
     }
 
-    for (unsigned int i = 0; i < num_of_bytes / 4; i++)
+    const u16 small_checksum = ((checksum & 0xFFFF0000) >> 16) + (checksum & 0x0000FFFF);
-    {
+    const u32 checksum_offset = hall_of_fame ? 0x0FF4 : 0x0FF6;
-        checksum += (global_memory_buffer[(4 * i) + 3] << 24) |
+    
-                    (global_memory_buffer[(4 * i) + 2] << 16) |
+    global_memory_buffer[checksum_offset] = small_checksum & 0x00FF;
-                    (global_memory_buffer[(4 * i) + 1] << 8) |
+    global_memory_buffer[checksum_offset + 1] = (small_checksum & 0xFF00) >> 8;
-                    (global_memory_buffer[(4 * i) + 0] << 0);
-    }
 
-    vu16 small_checksum = ((checksum & 0xFFFF0000) >> 16) + (checksum & 0x0000FFFF);
-    if (hall_of_fame)
-    {
-        global_memory_buffer[0x0FF4] = small_checksum & 0x00FF;
-        global_memory_buffer[0x0FF5] = (small_checksum & 0xFF00) >> 8;
-    }
-    else
-    {
-        global_memory_buffer[0x0FF6] = small_checksum & 0x00FF;
-        global_memory_buffer[0x0FF7] = (small_checksum & 0xFF00) >> 8;
-    }
 }
 
 bool read_flag(u16 flag_id)

source/main.cpp

@@ -21,7 +21,7 @@
 #include "pokedex.h"
 #include "global_frame_controller.h"
 #include "pkmn_font.h"
-#include "save_data_manager.h"
+#include "ptgb_save_data_manager.h"
 #include "mystery_gift_injector.h"
 #include "mystery_gift_builder.h"
 #include "multiboot_upload.h"
@@ -72,9 +72,9 @@ void load_graphics()
 	yes_no_menu.add_button(Button(button_no), false);
 }
 
-void initalization_script(void)
+void initialization_script(void)
 {
-	// Initalizations
+	// Initializations
 	REG_DISPCNT = DCNT_BLANK | DCNT_MODE0 | DCNT_BG0 | DCNT_BG1 | DCNT_BG2 | DCNT_BG3 | DCNT_OBJ | DCNT_OBJ_1D;
 
 	// Disable for save data read/write
@@ -452,7 +452,7 @@ static void __attribute__((noinline)) show_intro()
 int main(void)
 {
 	malloc_init_default_pool();
-	initalization_script();
+	initialization_script();
 
 	// Set colors based on current ROM
 	set_background_pal(0, false, false);
@@ -482,15 +482,15 @@ int main(void)
 			obj_hide_multi(ptgb_logo_l, 2);
 			global_next_frame();
 			game_load_error();
-			// initalization_script();
+			// initialization_script();
 		}
 	}
 
-	// Initalize memory and save data after loading the game
+	// Initialize memory and save data after loading the game
 	reset_textbox();
 	REG_BG2CNT = REG_BG2CNT | BG_PRIO(3);
 	init_bank();
-	initalize_memory_locations();
+	initialize_memory_locations();
 	load_custom_save_data();
 
 	set_background_pal(curr_GBA_rom.gamecode, false, true);
@@ -499,7 +499,7 @@ int main(void)
 	{
 		obj_hide_multi(ptgb_logo_l, 2);
 		text_loop(BTN_TRANSFER);
-		initalize_save_data();
+		initialize_save_data();
 		// TODO: We should be able to test for a Bootleg rom in here- if the save data isn't written, then it is bootleg.
 	}
 

source/pokedex.cpp

@@ -6,7 +6,7 @@
 #include "sprite_data.h"
 #include "pokemon_data.h"
 #include "global_frame_controller.h"
-#include "save_data_manager.h"
+#include "ptgb_save_data_manager.h"
 #include "button_handler.h"
 #include "translated_text.h"
 #include "text_engine.h"

source/pokemon_party.cpp

@@ -12,7 +12,7 @@
 #include "gb_gen1_payloads_RB_lz10_bin.h"
 #include "gb_gen1_payloads_Y_lz10_bin.h"
 #include "gb_gen2_payloads_lz10_bin.h"
-#include "save_data_manager.h"
+#include "ptgb_save_data_manager.h"
 #include "libraries/Pokemon-Gen3-to-Gen-X/include/save.h"
 
 static byte gen1_rb_debug_box_data[0x462] = {

source/ptgb_save_data_manager.cpp

@@ -1,5 +1,5 @@
 #include <tonc.h>
-#include "save_data_manager.h"
+#include "ptgb_save_data_manager.h"
 #include "flash_mem.h"
 #include "debug_mode.h"
 #include "button_menu.h"
@@ -11,19 +11,14 @@ byte save_data_array[SAVE_DATA_SIZE];
 void load_custom_save_data()
 {
     copy_save_to_ram(HALL_OF_FAME + 0x1000, &global_memory_buffer[0], 0x1000);
-    for (int i = 0; i < SAVE_DATA_SIZE; i++)
+    memcpy(save_data_array, global_memory_buffer + HOF_SECTION, SAVE_DATA_SIZE);
-    {
-        save_data_array[i] = global_memory_buffer[HOF_SECTION + i];
-    }
 }
 
 void write_custom_save_data()
 {
     copy_save_to_ram(HALL_OF_FAME + 0x1000, &global_memory_buffer[0], 0x1000);
-    for (int i = 0; i < SAVE_DATA_SIZE; i++)
+    memcpy(global_memory_buffer + HOF_SECTION, save_data_array, SAVE_DATA_SIZE);
-    {
+
-        global_memory_buffer[HOF_SECTION + i] = save_data_array[i];
-    }
     update_memory_buffer_checksum(true);
     erase_sector(HALL_OF_FAME + 0x1000);
     copy_ram_to_save(&global_memory_buffer[0], HALL_OF_FAME + 0x1000, 0x1000);
@@ -59,12 +54,9 @@ bool get_tutorial_flag()
     return save_data_array[TUTORIAL_FLAG];
 }
 
-void initalize_save_data()
+void initialize_save_data()
 {
-    for (int i = 0; i < SAVE_DATA_SIZE; i++)
+    memset(save_data_array, 0, SAVE_DATA_SIZE);
-    {
-        save_data_array[i] = 0;
-    }
     set_tutorial_flag(true);
     write_custom_save_data();
 }

source/rom_data.cpp

@@ -3,7 +3,7 @@
 #include "pokemon_party.h"
 #include "pokemon_data.h"
 #include "text_engine.h"
-#include "save_data_manager.h"
+#include "ptgb_save_data_manager.h"
 #include "gba_rom_values/gba_rom_values.h"
 #include "libraries/nanoprintf/nanoprintf.h"
 #include "gba_rom_values_eng_lz10_bin.h"